My long-term goal is to prevent the development of health problems among gay and bisexual males. While these youth are, compared to heterosexual adolescents, much more likely to experience depression, abuse substances, attempt suicide and become HIV infected, our understanding of the mechanisms involved in the development of these health problems among this population is incomplete and additional data are needed to be able to develop effective prevention interventions. With this in mind, this application describes how the lack of diverse samples and the dearth of longitudinal investigations with respect to research about young gay males are barriers to the provision of data to adequately inform the development of prevention interventions and how the Internet represents an enormous opportunity to study this population. Dr. Ron Stall will serve as mentor. He agrees that I require training in three areas if I am to achieve my research objectives: 1) using the Internet to study gay and bisexual youth;2) longitudinal research methods with marginalized populations;3) measurement of certain gay-related phenomenon. A strong team of consultants will provide the training: Drs. JeeWon Cheong, Michele Kipke, Michael Ross, Galen Switzer, Eric Wright, and Michele Ybarra. The research plan is to conduct a) a secondary data analysis of Dr. Kipke's longitudinal data-base of ethnically diverse gay and bisexual males;b) preliminary work to strengthen measures of internalized homophobia, sexual orientation and masculine socialization;and c) an Internet- based longitudinal study of 14 -17 year old heterosexual and gay and bisexual adolescents. This research will serve as a "laboratory" to practice the skills I learn as part of my training;support the field of Internet research by learning about recruiting and retaining hard-to-reach populations;promote understanding of the development of health problems among gay and bisexual youth and how these processes compare to those among heterosexual youth;and provide pilot data to support an R01 or R34 research application. This application supports the mission of the National Institute of Mental Health by providing data about the development of health problems among gay and bisexual youth that will be used to help develop effective interventions and by providing training to position this candidate to engage in future research to improve the mental health of this population.